[dm-devel] multipath: Determine which device to use for grubdevice.map file

[malahal at us.ibm.com]

> mpatha (36006016094511600449d92ae1937d611) dm-0 DGC,DISK
> [size=50G][features=1 queue_if_no_path][hwhandler=1 emc][rw]
> \_ round-robin 0 [prio=2][active]
> \_ 2:0:1:0 sdd 8:48  [active][ready]
> \_ 3:0:1:0 sdf 8:80  [active][ready]
> \_ round-robin 0 [prio=0][enabled]
> \_ 2:0:0:0 sdc 8:32  [active][ready]
> \_ 3:0:0:0 sde 8:64  [active][ready]
>
> Out of the 4 paths, only two (sdd and sdf) are active. This output is 
> not very good to parse through in a script to determine which disks I 
> can specify in my device.map file. Is there a command or better way to 
> determine which underlying paths I can use in my device.map file.

You can probably get it from "dmsetup status <device>", but it may be
even harder to parse!

Thanks, Malahal.